In the past, a semiconductor wafer has been required to be a wafer with a planarized surface in order to create a fine pattern by a photomechanical process. In particular, surface waves called “nanotopography” are waves having components with wavelengths λ=0.2 to 20 mm, the waves whose PV values (Peak to Valley values) are 0.1 to 0.2 μm or less, and, recently, a technique of improving the flatness of a semiconductor wafer by reducing this nanotopography has been proposed. As such a wafer planarization method, a processing method including a primary grinding step of grinding a second surface of a wafer with a first surface of the wafer obtained by slicing an ingot being held on a horizontally holding surface of a chuck table by suction and then grinding the first surface of the wafer with the second surface of the wafer being held on the horizontally holding surface by suction, a resin applying step of covering, after the primary grinding step, the whole of the second surface of the wafer with resin, and a step of grinding, after the resin applying step, the first surface of the wafer with the second surface of the wafer being held on the horizontally holding surface by suction by using the second surface of the wafer as a reference surface and, after removing the resin, grinding the second surface of the wafer by using the first surface of the wafer as the reference surface has been disclosed (refer to, for example, Patent Document 1).
Patent Document 1: JP-A-2011-249652 (claim 1, paragraphs [0008], [0028], and FIG. 2)